Irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders in clinical practice. In recent years, it has been recognized in the art as a gut brain disease with specific pathological and psychological factors. It is a set of symptoms including abdominal pain, abdominal distension, bowel evacuation habit changes and stool abnormalities, mucous stool and the like. According to clinical manifestation, IBS can be generally divided into four types, i.e. diarrhea type, constipation type, alternating diarrhea and constipation type and abdominal pain type, in which the diarrhea type accounts for about ⅔. Epidemiological investigation shows that, 10% to 20% of population around the world have suffered from IBS symptoms. In Europe and the United States, this disease accounts for more than 50% of the gastrointestinal outpatient. The incidence of IBS in Chinese is 7.01%, in which a significant number of patients are associated with depression, anxiety and sleep disorders. Since the patients often complain of a gastrointestinal symptom as the main symptom, they are usually treated and modulated by doctors as gastrointestinal motility abnormalities, therefore, the efficacy is poor.
The occurrence of IBS is closely related to mental, psychological, emotional factors and environmental stress. IBS patients often suffer from nervousness, emotional irritability, unease, anxiety and depression. The study shows that, 50% to 90% of IBS patients have mental disorders such as anxiety and depression; more than 50% of patients have sleep disorders such as ease to wake up and morning fatigue. The increase of glucocorticoid induced by stress (HPA axis hyperactivity) can directly promote the excitement of brain amygdala, which is the main center for regulating the body and visceral stress, the excessive and continued increase of glucocorticoid can induce changes in colorectal tension sensitivity. Therefore, IBS could be appropriately relieved and treated through reverse regulation of the hyperactive HPA axis and inhibition of excessive secretion of glucocorticoids.
In addition to mental and environmental stress factors, IBS could also be induced by change of gastrointestinal motility, gastrointestinal disorder and gastrointestinal infection, intolerance to one or more foods, allergy and abnormality of gastrointestinal endocrine hormone activity, for example content increase of motilin (MTL) and sigmoid colon mucosal vasoactive intestinal peptide (VIP).
Since IBS is a complex multi-target integrated disease of multiple mental-physiological factors, there still lacks an efficient drug for treating irritable bowel syndrome in modern medicine at present (“Research Ideas and Methods on Efficacy of Traditional Chinese Medicine”, P449). Symptomatic treatment is usually used in clinical practice. The drugs commonly used include antispasmodic drug, gastrointestinal-kinetic promoter or inhibitor, antiflatulent, laxative, antidiarrheal drug, drug for regulating visceral sensitivity and the like. The antidepressant and antianxietic drugs can not only improve the mental state of patient, but also regulate the gastrointestinal function of patient. They are also used by doctors as drugs for treating IBS in combination with other types of drugs, for example, calcium ion antagonist pinaverium bromide is combined with fluoxetine in clinical practice. Although the combined administration can increase efficacy to a certain extent, the side effects are also superimposed, which seriously affect the life quality of the user. The combined administration also increases the cost of treatment, and increases the economic burden of patients and society.
The ideal drug for treating IBS should meet the following requirements:
1. it has multiple functions of antidepressant, antianxiety, antiallergic, anti-inflammatory, antidiarrheal, analgesic, regulating gastrointestinal function and reducing visceral sensitivity and improving sleep;
2. it has few side effects, is safe, and can be administered to the patient over a long term for conditioning treatment;
3. its quality is controllable, its administration is convenient, its cost is moderate, which will not give the patient an excessive economic burden.
Traditional Chinese Medicine concentrates on regulating the emotion of patient during the treatment of IBS, for example, the famous “pain-diarrhea formulation” (described in “Jing Yue's Complete Works”) has good efficacy in the treatment of diarrhea-predominant irritable bowel syndrome. However, the formulation comprises a large number of herbal medicines, which are used in a large amount, and the preparation method is rather primitive. Therefore, the quality of the formulation is not controllable, and the administration is not convenient.
The inventor learns from the Traditional Chinese Medicine formulation, which treats IBS by soothing liver to relieve depression and improving spleen function to calm the nerves, and uses modern pharmacology as guidance. Based on the previous research on antidepressant and drug for improving sleep, the inventor successfully uses albiflorin or a pharmaceutically acceptable salt thereof for treating irritable bowel syndrome by means of computer system targeting research via repeated validation of efficacy.
Albiflorin or a pharmaceutically acceptable salt thereof of the present invention compensates for the defect and deficiency of existing drugs for treating IBS. It is an ideal natural product for preventing and treating IBS, because it starts from multiple targets, and has multiple functions of antidepressant, antiallergic, anti-inflammatory, antidiarrheal, analgesic, regulating gastrointestinal function and reducing visceral sensitivity, and improving sleep. It is safe and has few side effects, and can be administered to the patient over a long term for conditioning treatment of IBS.
Albiflorin is a monoterpenoid compound, with the molecular formula of C23H28O11 and the molecular weight of 480.46. The molecular structure thereof is shown as Formula (I). It is a natural active substance derived from the roots of Paeonia lactiflora Pall, Paeonia veitchii Lynch and P. suffrsticosa Andrz of Ranuculaceae plants.

Albiflorin has a cyclic structure of lactone, but without a hemiacetal structure. It is converted under anaerobic condition into two products, paeonilactone A and paeonilactone B, respectively. The structures of paeonilactone A and B are shown as Formula (II) and Formula (III), respectively:

Modern pharmacological studies indicate that, albiflorin has analgesic, sedative and anticonvulsant effects, immune system-related effect, smooth muscle-related effect, anti-inflammatory effect, effect against pathogenic microorganisms, and liver protection effect. Clinically speaking, it is mainly used for anti-epilepsia, analgesia, drug abuse rehabilitation, nausea-stopping, the treatment of rheumatoid arthritis, the treatment of bacillary dysentery and enteritis, the treatment of viral hepatitis, the treatment of age-related diseases, the resistance to barium sulfate flocculation and mucus dissolution. The use of albiflorin for the prevention and treatment of irritable bowel syndrome has not yet been reported.